Can anybody advise what is email ID (email->ID) here in below code ? I didn't understand what this is and why we require this ? Where do we find this value ? can we find these in marketing cloud admin.

$email = new ExactTarget_Email();
$email->ID = "12345";$emailSendDef->Email = $email;

Along with that where we can find the list id in the below code ?

$sendDefList = new ExactTarget_SendDefinitionList();
$list = new ExactTarget_List();$list->ID = "12345";

And CustomerKey,Name

$emailSendDef = new ExactTarget_EmailSendDefinition();
$emailSendDef->CustomerKey = "12345";
$emailSendDef->Name = "test";